Advanceable roof support assemblies



N 1965 D. H. H. BOLTON ETAL 3,217,605

ADVANGEABLE ROOF SUPPORT ASSEMBLIES Filed Sept. 1, 1964 2 Sheets-Sheet l 4 J E @MEBE 4 3 1 Hal.

13 11 :13 11 1 1/ g 4 g 4 14 14 L w 4 4 INVEN OE MRI-MEL C. PoTTS 5y .DouGLAS [4- H. BoLT'flU F/ZM/k PAwum: b'N ls H- n AWN United States Patent 3,217,606 ADVANCEABLE ROOF SUPPORT ASSEMBLIES Douglas Herbert Hewlett Bolton, Winchcombe, Frank Pawling, Charlton Kings, Michael Charles Potts, Prestbury, Dennis Henry Cannon, Cheltenham, and Richard Henry Bryan Winder, Chalfont St. Peter, England, assignors to Dowty Mining Equipment Limited, Gloucester, England, a British company Filed Sept. 1, 1964, Ser. No. 393,501 Claims priority, application Great Britain, Sept. 3, 1963, 34,818/63 Claims. (Cl. 91-170) This invention relates to advanceable roof support assemblies suitable for use in mines.

The present invention provides an advanceable roof support assembly including a series of advanceable fluidpressure-operated roof supports, each roof support including a first valve assembly whose operation causes the roof support to undergo an advancing operation, the initiation of operation of the first valve assembly being caused by the pressurisation of an advance-start line connected to the first valve assembly, each roof support also including a second valve assembly connected to the advancestart line of that roof support and connected by a signal line to the second valve assembly of the next roof sup port in the series, each second valve assembly being operable to pressurise alternatively the signal line connected to the next roof support with consequent pressurisation of the advance-start line and advance of the preceding roof support or the next roof support respectively, and the operation of each second valve assembly being arranged to prevent pressurisation of the advance-start line of the roof support in which the operated second valve assembly is included.

Each second valve assembly may include two valves, one valve being connected between the advance-start line and the signal line connected to the preceding roof support and the other valve being connected between the advance-start line and the signal line connected to the next roof support, each valve being opened by pressurisation of the respective signal line when said signal line is pressurised by operation of the second valve assembly of the preceding roof support or the next roof support respectively, and each valve being locked in the closed position by the pressurisation of the respective signal line caused by operation of the second valve assembly in which said valves are included.

The second valve assembly of each roof support may be only operable when the roof-supporting fluid pressure in the roof support is satisfactory. The second valve assembly of each roof support may be rendered inoperable, when the roof-supporting fluid pressure in the roof support is unsatisfactory, by closure of a safety valve in a line connecting the second valve assembly with a source of fluid under pressure.

At least some of the roof supports may be used as anchorages in applying an advancing force to another anchorage (for example a conveyor or another roof support) and each such roof support may include means preventing the use of the roof support as an anchorage unless there is a satisfactory roof-supporting fluid-pressure in the roof support. The said preventing means may be the safety valve mentioned in the preceding paragraph.

One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings of which,

FIGURE 1 is a diagrammatic view of a series of advanceable roof supports arranged along the working face of a coal'rnine,

FIGURE 2 is a diagrammatic view of three roof supports of the series, showing the hydraulic connections to each roof support and,

FIGURE 3 is a diagrammatic view of the hydraulic circuit of one of the roof supports.

With reference to the accompanying drawings, a series of advanceable hydraulically-operated roof supports 1 are arranged along the working face 2 of a coal-mine. Each roof support 1 includes a floor-engaging member 3 which carries three hydraulically-operated props 4, and the three props 4 carry a roof-engageable member (not shown). Each roof support 1 is connected to a snakeable conveyor 5 by a hydraulically-operated jack 6 operable to advance the roof support towards the conveyor 5. Some roof supports, for example every fourth roof support as shown, have a second hydraulically-operated jack 7 which is operable to apply an advancing force to the conveyor 5 when its roof support is set against the roof. FIGURE 1 also shows a cutting machine 8 which is moving from left to right along the working face 2.

A hydraulic pressure supply line 9 extends along the mine and is connected to each roof support 1 by branch lines 11. A hydraulic return line 12 also extends along the mine and is connected to each roof support 1 by branch lines 13. Also, each roof support 1 is connected to its adjacent roof support by a signal line 14.

Each roof support 1 with a conveyor-advancing jack 7 includes a first valve assembly which includes a prop release valve 15, a prop setting valve 16 and a conveyoradvance valve assembly 17. The setting valve 16 is connected to the branch supply line 11 and to a prop supply line 18 which communicates with each prop 4 through separate non-return valves 19. The prop release valve 15 is connected to a prop release line 21 and to the branch return line 13. The prop release line 21 is connected to the props 4 through separate non-return valves 22. A prop relief valve 23 is connected in parallel with the prop release valve 15 between the prop release line 21 and the branch return line 13. The relief valve 23 relieves excess pressure in any one of the props 4, and the non-return valves 19, 22 prevent the props 4 from interacting, that is to say from discharging hydraulic fluid from one prop into another.

The prop release and setting valves 15, 16 can be operated by actuation of a pivotally-mounted lever 24. Anti-clockwise movement of the lever 24 opens the release valve 15 and allows fluid to be released from the props 4 through the non-return valves 22 and release line 21 into the branch return line 13. Clockwise movement of the lever 24 opens the setting valve 16 and allows fluid under pressure to pass from the branch supply line 13 into the props 4 through setting line 18 and non-return valves 19. If necessary, setting line 18 may include a pressure-reducing valve 25. When the setting valve 16 is closed, setting line 18 communicates with branch return line 13 through apertures 10 in the actuating rod 20 of the setting valve 16.

The lever 24 is actuated to operate the release valve 15 by actuation of a hydraulically-operated actuator 26. The actuator 26 is operated by pressurisation of a line 27, as will be described later, The lever 24 is actuated to operate the setting valve 16 by actuation of a hydraulically-operated actuator 28, which is powerful enough to overcome the effect of actuator 26 on lever 24. The actuator 28 is operated by pressurisation of a line 29, as will also be described later.

The prop release line 21 is connected to a safety valve 79 by a line 31. The safety valve '79 is connected between branch supply line 11 and a further branch supply line 32. The safety valve 79 is spring-biased to a closed position and is opened by the pressure in line 31 when this pressure is above a predetermined value representing a satisfactory roof-supporting pressure in the props 4. The further branch supply line 32 is connected to a second valve assembly 33 and to the conveyor-advance valve assembly 17.

The conveyor-advance valve assembly 17 includes a valve 34 connected to supply line 32 and to the conveyoradvancing jack 7 through a valve assembly 35 and line 36. Valve 34 can be opened by clockwise movement of a pivotally-mounted lever 37 and, when valves 79 and 34 are open, fluid under pressure is supplied to the conveyor-advancing jack 7 which is thus caused to apply an advancing force to the conveyor 5. The necessary movement of lever 37 may be caused by an automatic operation, for example by the cutting machine 8 as it travels along the working face 2, or by a manual operation, for example direct manual operation of lever 37 or a manually-operated remote control. In practice, several conveyor-advancing jacks 7 will probably be in operation at the same time.

When lever 37 has been moved to its valve-opening position, it is held in this position by a latch 38, which can be released hydraulically by pressurisation of line 27 which is connected to the latch 33. The valve assembly 35 allows fluid under pressure to pass from valve 34 to line 36 through a ball-valve 39, and also allows fluid to be easily expelled from the pushing side of jack 7, when jack 7 is being contracted, through line 36 and a piston valve 41 to branch return line 13.

Each second valve assembly 33 includes two valves 42, 43 connected to branch supply line 32 and to lines 44, 45 respectively. The valves 42, 43 can be opened by manual-operation of a pivotally-mounted handle 46 which operates on the valves 42, 43 through actuating rods 47, 48 respectively. When the handle 46 is in its neutral position, as shown in the drawing, both valves 42, 43 are closed and lines 44, 45 are in communication with the branch return line 13 through apertures 49 in the actuating rods 47, 48.

Each second valve assembly 33 also includes two valves 51, 52 which include valve closure members 53, 54 respectively, pistons 55, 56 respectively and springs 57, 58 respectively. The spring 57 or 58 urges the piston 55 or 56 towards the valve closure member 57 or 58 in a valve-closing sense. The line 44 is connected by a line 59 to the side of piston 55 remote from the valve closure member 53, and is also connected through a nonreturn valve 61 to the signal line 14 leading to the adjacent left hand roof support. This signal line 14 is connected to the side of valve closure member 53 remote from the piston 55. Similarly, the line 45 is connected by a line 62 to the side of piston 56 remote from the valve closure member 54, and is also connected through a nonreturn valve 63 to the signal line 14 leading to the adjacent right hand roof support. This signal line 14 is connected to the side of valve closure member 54 remote from the piston 56.

The downstream side of valve closure members 53, 54 are both connected to line 27. A line 64 is connected from the line 27 through a non-return valve 65 and a valve assembly 66 to the jack-contracting sides of jacks 6 and 7. The valve assembly 66 allows fluid under pressure to pass along line 64 from non-return valve 65 to the jacks 6 and 7 through a ball valve 67, and also allows fluid to be easily expelled from the pulling side of jacks 6 and 7, when the jacks 6 and 7 are being extended, through line 64 and a piston valve 68 to the branch return line 13. A restrictor 69 connects the portion of line 64 between non-return valve 65 and valve 66 to the branch return line 13 so that fluid pressure in line 27 can leak away when the source of pressure is removed.

A valve 71 associated with the jack 6 is opened by full contraction of the jack 6 to bring line 64 into communication with line 29.

If necessary, a restrictor 72 may be included in the branch supply line 11.

In operation of the roof support assembly described above, and assuming that all the roof supports are set against the roof, the conveyor 5 is first advanced in a snaking manner relative to the roof supports. Each jack 7 in turn is caused to apply an advancing force to the conveyor 5 by actuation of the lever 37 to open valve 34 with consequent pressurisation of jack 7 through ball valve 39 of valve assembly and line 36, provided that the safety valve 79 of the roof support is open, that is to say provided that the roof support 1 is adequately set against the roof. If the safety valve 79 was omitted and the roof support was not adequately set against the roof, actuation of jack 7 may cause the roof support to move backwards with possible resultant damage or injury to personnel. While the jack 7 is extending in advancing the conveyor 5, jack 6 also extends, and the fluid expelled from the jack-contracting sides of the jacks 6, 7 passes easily along line 64 and past piston valve 68 to the branch return line 13. Once actuated, the lever 37 is held in the conveyor-advancing position by the latch 38. FIGURE 1 shows a condition where the initial part of the conveyor 5 has been advanced, and thus the first few roof supports 1 of the series can also be adavnced.

Each roof support 1 can be advanced by an operator actuating the handle 46 of either the adjacent left hand roof support or the adjacent right hand roof support. Thus the operator has adequate shelter while a roof support is undergoing an advancing operation. Assuming first that a roof support is to be advanced by actuation of the handle 46 of the adjacent left hand roof support,

the operator moves the handle 46 in a clockwise direction to depress actuating rod 48 and open valve 43. Then provided that safety valve 79 is open, line is pressurised from branch supply line 32 with resutlant pressurisation through non-return valve 63 of the signal line 14 leading to the right. Line 62 is also pressurised and this pressure acts on piston 56 to hold valve closure member 54 on its seat and so prevent pressurisation of the line 27 in the roof support whose handle 46 is being actuated. It will be noted that, if safety valve 79 is not open, actuation of the handle 46 has no effect so that an operator cannot initiate advance of an adjacent roof support if the roof support he is operating from is not adequately set against the roof.

Thus, considering now the hydraulic circuit shown in FIGURE 3, actuation of the handle 46 on the adjacent left hand roof support causes pressurisation of the signal line 14 on the left hand side of FIGURE 3. This pressure cannot pass non-return valve 61, but opens valve closure member 53 with resultant pressurisation of line 27.

Pressurisation of line 27 initiates three operations. Firstly, the latch 38 is released and valve 34 closes so that jack 7 stops applying an advancing force to the conveyor 5. Secondly, the release actuator 26 is operated to move lever 24 and open the prop release valve 15 so that the props 4 are released from the roof. Thirdly, the jack-contracting sides of jacks 6 and 7 are pressurised from line 27 through line 64, non-return valve and ball valve 67. Jack 7 contracts immediately, with fluid expelled from the jack-extending side passing easily along line 36 and past the piston valve 41 to the branch return line 13. Jack 6, in contracting, causes the roof support to advance towards the conveyor 5. The pushing side of jack 6 is permanently open to atmosphere.

When the jack 6 is fully contracted, that is to say when the roof support has fully advanced, valve 71 is opened by the jack 6 with consequent pressurisation of line 29 from line 64. Pressurisation of line 29 operates the actuator 28 to cause movement of lever 24, overcoming the force exerted by actuator 26, so that the release valve 15 closes and the setting valve 16 opens. The props 4 are thus reset against the roof. When the props 4 are initially released from the roof, safety valve 79 closes and only re-opens when the props 4 are satisfactorily reset against the roof.

Thus, line 27 acts as an advance-start line which, when pressurised, initiates operation of the first valve assembly to cause the roof support to undergo an advancing operation.

The operator then allows the handle 46 on the adjacent left hand roof support to return to the neutral position. The non-return valves 61, 63 may be so designed that they close only when the pressure in the respective signal line 14 has fallen a substantial amount, by drainage through the ports 49 in the actuating rod 47 or 48, so as to prevent any back pressure in a signal line 14 from passing the valve 53 or 54 in the roof support from which the operator is operating, since such an occurrence may initiate an advancing operation of the operators roof support.

The return of the handle 46 to its neutral position allows the various valves of the roof support which has advanced to return to the positions shown in FIGURE 3. Thus valve 51 closes and line 27 drains through a portion of line 64, non-return valve 65 and restrictor 69. Line 29 and the other portion of line 64 drain past piston valve 68. Also, prop setting Valve 16 shuts and line 18 drains through ports in actuating rod 20.

If a roof support is to be advanced by actuation of the handle 46 on the adjacent right hand roof support, the handle 46 is moved in an anti-clockwise manner with resultant pressurisation of the signal line 14 leading to the left. This pressure in signal line 14 passes valve 52 on the roof support to be advance with consequent pressurisation of line 27 and advance of the roof support.

A man can therefore advance each roof support in turn, from the shelter of the adjacent roof support, by working in either direction along the series of roof supports. It will be seen that, in addition to the main supply and return lines 9, 12, there is only one further line passing from roof support to roof support, namely the signal line 14.

We claim as our invention:

1. An advanceable roof support assembly including a series of advanceable fiuid-pressure-operated roof supports, each roof support including a first valve assembly operable to cause the roof support to undergo an advancing operation, an advance-start line connected to the first valve assembly to initiate operation of the first valve assembly upon pressurisation of the advance-start line, and a second valve assembly connected to the advancestart line of that roof support, a signal line connected from the second valve assembly of each roof support to the second valve assembly of the next roof support, and

means for operating each second valve assembly to pressurise alternatively the single line connected to the preceding roof support or the signal line connected to the next roof support with consequent pressurisation of the advance-start line and adavnce of the preceding roof support or the next roof support respectively, and each second valve assembly including means to prevent pressurisation of the advance-start line of the roof support in which the second valve assembly is included when said second valve assembly is operated.

2. A roof support assembly according to claim 1 wherein each second valve assembly includes two valves, one of which is connected between the advance-start line and the signal line connected to the preceding roof support and the other of which is connected between the advancestart line and the signal line connected to the next roof support, each valve being opened by pressurisation of the respective signal line when said signal line is pressurised by operation of the second valve assembly of the preceding roof support or the next roof support, and each valve being locked in the closed position by the pressurisation of the respective signal line caused by operation of the second valve assembly in which said. valves are included.

3. A roof support assembly according to claim 1 wherein each roof support includes safety means responsive to the roof-supporting fluid pressure in the roof support to prevent operation of the second valve assembly when said pressure is below a predetermined value.

4. A roof support assembly according to claim 3 wherein the safety means includes a valve in a line connecting the second valve assembly with a source of fluid under pressure.

5. A roof support assembly according to claim 1 wherein at least some of the roof supports are used as anchorages in applying an advancing force to another anchorage,

and each such roof support includes safety means responsive to the roof-supporting fluid pressure in the roof sup port to prevent use of the roof support as an anchorage when said pressure is below a predetermined value.

References Cited by the Examiner UNITED STATES PATENTS 1,905,065 4/1933 Scholl 9l189 X 2,657,028 10/1953 Joy 6l45.2 X 2,752,757 7/1956 Joy 914l4 X 2,859,022 11/1958 Frye 6l-45.2 X

EDGAR W. GEOGHEGAN, Primary Examiner.

SAMUEL LEVINE, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,217,606 November 16, 1965 Douglas Herbert Hewlett Bolton et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 2, for "single" read signal line 5, for "adavnce" read advance Signed and sealed this 23rd day of August 1966.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents 

1. AN ADVANCEABLE ROOF SUPPORT ASSEMBLY INCLUDING A SERIES OF ADVANCEABLE FLUID-PRESSURE-OPERATED ROOF SUPPORTS, EACH ROOF SUPPORT INCLUDING A FIRST VALVE ASSEMBLY OPERABLE TO CAUSE THE ROOF SUPPORT TO UNDERGO AN ADVANCING OPERATION, AN ADVANCE-START LINE CONNECTED TO THE FIRST VALVE ASSEMBLY TO INITIATE OPERATION OF THE FIRST VALVE ASSEMBLY UPON PRESSURISATION OF THE ADVANCE-START LINE, AND A SECOND VALVE ASSEMBLY CONNECTED TO THE ADVANCESTART LINE OF THAT ROOF SUPPORT, A SIGNAL LINE CONNECTED FROM THE SECOND VALVE ASSEMBLY OF EACH ROOF SUPPORT TO THE SECOND VALVE ASSEMBLY OF THE NEXT ROOF SUPPORT, AND MEANS FOR OPERATING EACH SECOND VALVE ASSEMBLY TO PRESSURISE ALTERNATIVELY THE SINGLE LINE CONNECTED TO THE PRECEDING ROOF SUPPORT OR THE SIGNAL LINE CONNECTED TO THE NEXT ROOF SUPPORT WITH CONSEQUENT PRESSURISATION OF THE ADVANCE-START LINE AND ADVANCE OF THE PRECEDING ROOF SUPPORT OR THE NEXT ROOF SUPPORT RESPECTIVELY, AND EACH SECOND VALVE ASSEMBLY INCLUDING MEANS TO PREVENT PRESSURISATION OF THE ADVANCE-START LINE OF THE ROOF SUPPORT IN WHICH THE SECOND VALVE ASSEMBLY IS INCLUDED WHEN SAID SECOND VALVE ASSEMBLY IS OPERATED. 